Earth:Sheinwoodian

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Sheinwoodian
433.4 ± 0.8 – 430.5 ± 0.7 Ma
Laurasia 430Ma.jpg
Paleogeography of the late Sheinwoodian
Chronology
Silurian graphical timeline
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Subdivision of the Silurian according to the ICS, as of 2021.[3]
Vertical axis scale: millions of years ago.
Etymology
Name formalityFormal
Name ratified1980[4]
Usage information
Celestial bodyEarth
Regional usageGlobal (ICS)
Time scale(s) usedICS Time Scale
Definition
Chronological unitAge
Stratigraphic unitStage
Time span formalityFormal
Lower boundary definitionImprecise. Currently placed between acritarch biozone 5 and LAD of Pterospathodus amorphognathoides. See Llandovery for more info.
Lower boundary definition candidatesA conodont boundary (Ireviken datum 2) which is close to the murchisoni graptolite biozone.
Lower boundary GSSP candidate section(s)None
Lower boundary GSSPHughley Brook, Apedale, United Kingdom
[ ⚑ ] 52°34′52″N 2°38′20″W / 52.5811°N 2.6389°W / 52.5811; -2.6389
GSSP ratified1980[4]
Upper boundary definitionFAD of the graptolite Cyrtograptus lundgreni
Upper boundary GSSPSheinton Brook, Homer, England
[ ⚑ ] 52°36′56″N 2°33′53″W / 52.6156°N 2.5647°W / 52.6156; -2.5647
GSSP ratified1980[4]

In the geologic timescale, the Sheinwoodian is the age of the Wenlock Epoch of the Silurian Period of the Paleozoic Era of the Phanerozoic Eon that is comprehended between 433.4 ± 0.8 Ma and 430.5 ± 0.7 Ma (million years ago), approximately. The Sheinwoodian Age succeeds the Telychian Age and precedes the Homerian Age.[5]

Definition

The Wenlock-Llandovery boundary is defined by the first occurrence of Cyrtograptus centrifugus. The stage is named after Sheinwood village, north of Much Wenlock. The Buildwas Formation of Shropshire, United Kingdom contains the type section.[6]

References

  1. Jeppsson, L.; Calner, M. (2007). "The Silurian Mulde Event and a scenario for secundo—secundo events". Earth and Environmental Science Transactions of the Royal Society of Edinburgh 93 (02): 135–154. doi:10.1017/S0263593300000377. 
  2. Munnecke, A.; Samtleben, C.; Bickert, T. (2003). "The Ireviken Event in the lower Silurian of Gotland, Sweden-relation to similar Palaeozoic and Proterozoic events". Palaeogeography, Palaeoclimatology, Palaeoecology 195 (1): 99–124. doi:10.1016/S0031-0182(03)00304-3. 
  3. "Chart/Time Scale". International Commission on Stratigraphy. http://www.stratigraphy.org/index.php/ics-chart-timescale. 
  4. 4.0 4.1 4.2 Holland, C. (1982). "The State of Silurian Stratigraphy". Episodes 1982: 21-23. https://stratigraphy.org/gssps/files/sheinwoodian-ludfordian.pdf. Retrieved 11 December 2020. 
  5. Gradstein, Felix M.; Ogg, James G.; Smith, Alan G. (2004). A Geologic Time Scale 2004. ISBN 9780521786737. 
  6. Silurian System